Lubricant for metalworking



Patented F eb. 1944 LUBRICANT FOR METALWORKING Clarence Walter Wilson,Norco, Calif., assignor to California Fruit Growers Exchange, LosAngeles, Califi, a corporation of California No Drawing. ApplicationFebruary 16, 1942, Serial No. 431,104

8 Claims.

This invention has to do with the forming and drawing operationsperformed on sheet metals, and is specifically directed toward thelubrication of the metal to facilitate such operations.

An object of this invention is to provide a new lubricant for suchoperations on metal as swaging and drawing.

In many metal forming processes it is necessary to lubricate the metalbeing formed. For example, die stamping involves the sliding on eachother of metal surfaces of the blank and the die under high pressure.Lack of an eiiective lubricant may result in sticking of the die to themetal, rough surfaces on the formed object, and wearing of the dieparts. Lubricants are generally used to avoid these diiliculties. Theselubricants are usually heavy oils.

I have discovered that water sols of soluble pectates, such as those ofthe alkali metals, ammonium, and alkaline organic bases, are excellentlubricants for this type of work.

In my Patent No. Re. 21,077, I disclose the preparation of pectates frompectinous source materials by treatment of said source materials withalkalies. Alkali metal, ammonium, and alkaline organic base pectates canbe formed by similar reactions. The source material which has beentreated I call pectate pulp. This pulp may be used in many instances inlieu of the pure pectates, which may be isolated from the pulp by properprocedures, as disclosed in the above dies. The cut blanks werelubricated with a 5% dispersion of sodium pectate pulpprepared in thefollowing proportions:

Kg. Pectate pulp 10.0 NazP40v 0.5

Na2CO 0.3

This mixture was added to 260 l. of boiling water. Boiling of themixture was continued for a short time, and vigorous agitation wasemplcy'ed to disintegrate the inert material, and free the pectatetherefrom. v

In a comparison under similar circumstances it was found that thepectate sol was a lubricant equally as effective as the heavy oilpreviously used. The test was rather a severe one, a fairly deep drawingbeing obtained in a single operation. Conditions were such that absenceof an ruined in short order.

efiective lubricant would allow the dies to be pectate sols as thelubricant were smooth and no sticking was encountered.

A comparatively new development is the use of a rubber male die part,partially or not at all formed, in conjunction with a metal female diepart. In this sort of stamping or forming there is a great deal offriction between the rubber and the metal being formed, since the rubberflows as the metal is formed. Lubrication under such circumstances is animportant problem. One attack has been the development-of rubbers orsynthetic rubber-like materials which resist the deteriorating efl'ectof the oils generally used.

As' is well known, most oils used for such workhave an adverse action onordinary rubber. The use of pectate sols avoids the necessity for usingor discovering new materials for the die parts, since the pectates donot have any deleterious efiect on common types of rubber.

Another advantage is encountered in the production of parts which it isdesired to electroplate after shaping. Whereas when oils are used in theshaping operation it is necessary to provide special cleaning baths forcomplete removal of the oil prior to plating, the pectates may beremoved by the use of hot water.

A specific application of the same problem is the substitution ofpectate sols for lime in wire drawing.

The pectate pulp may ordinarily be used, and is a very economicallubricant. In some instances it may be desirable to eliminate the inertinsoluble matter, and use only the pectate extracted from the pulp.

.Sols including from 1% to 6% of the pectate pulp, or from 1% to 4% ofthe purified pectates are suitable. These limits are not absolute, but

represent good practice.

While in the example given I have stated that the metal blank waslubricated, -obviously the same results maybe obtained by adding thelubricant to the die parts, or both may be practiced.

I claim as my invention:

1. A process for lubricating contacting metal parts in metal formingoperations, comprising interposing between the contacting. parts anaqueous sol including a water-soluble pectate.

2. A process for lubricating contactingparts in metal formingoperations, comprising inter;-

posing between the contacting parts an aqueous Parts formed using metaland resilient material in metal forming operations, comprisinginterposing between the metal and resilient material an aqueous solincluding a water-soluble pectate.

4. A process for lulbricatin'g contacting metal parts in die stampingoperations, comprising interposing between the contacting parts anaqueous $01 including a water-soluble=pectate.

5. A process for lubricating contacting parts in die stampingoperations, comprising interposing between the contacting parts anaqueous $01 including a water-soluble pectate.

6. A process for lubricating contacting parts of metal and resilientmaterial in die stamping operations, comprising interposing between themetal and resilient material an aqueous sol inaqueous sol including awater soluble pectate.

8. A process for lubricating contacting parts in metal drawingoperations, comprising interposing between the contacting parts anaqueous sol including a water soluble pectateQ CLARENCE WALTER WILSON.

